https://dev.opencascade.org/doc/occt-7.5.0/refman/html/class_i_g_e_s_select___counter_of_level_number.html
IGESSelect_CounterOfLevelNumber Class Reference - Open CASCADE Technology Documentation
IGESSelect_CounterOfLevelNumber Class Reference - documentation, user manuals, examples, Open CASCADE Technology
open cascade technologyclass referencedocumentation